1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
4 */
5
6#include <linux/module.h>
7#include <linux/of_address.h>
8#include <linux/platform_device.h>
9#include <linux/thermal.h>
10
11struct thermal_mmio {
12 void __iomem *mmio_base;
13 u32 (*read_mmio)(void __iomem *mmio_base);
14 u32 mask;
15 int factor;
16};
17
18static u32 thermal_mmio_readb(void __iomem *mmio_base)
19{
20 return readb(addr: mmio_base);
21}
22
23static int thermal_mmio_get_temperature(struct thermal_zone_device *tz, int *temp)
24{
25 int t;
26 struct thermal_mmio *sensor = thermal_zone_device_priv(tzd: tz);
27
28 t = sensor->read_mmio(sensor->mmio_base) & sensor->mask;
29 t *= sensor->factor;
30
31 *temp = t;
32
33 return 0;
34}
35
36static const struct thermal_zone_device_ops thermal_mmio_ops = {
37 .get_temp = thermal_mmio_get_temperature,
38};
39
40static int thermal_mmio_probe(struct platform_device *pdev)
41{
42 struct thermal_mmio *sensor;
43 int (*sensor_init_func)(struct platform_device *pdev,
44 struct thermal_mmio *sensor);
45 struct thermal_zone_device *thermal_zone;
46 int ret;
47 int temperature;
48
49 sensor = devm_kzalloc(dev: &pdev->dev, size: sizeof(*sensor), GFP_KERNEL);
50 if (!sensor)
51 return -ENOMEM;
52
53 sensor->mmio_base = devm_platform_get_and_ioremap_resource(pdev, index: 0, NULL);
54 if (IS_ERR(ptr: sensor->mmio_base))
55 return PTR_ERR(ptr: sensor->mmio_base);
56
57 sensor_init_func = device_get_match_data(dev: &pdev->dev);
58 if (sensor_init_func) {
59 ret = sensor_init_func(pdev, sensor);
60 if (ret) {
61 dev_err(&pdev->dev,
62 "failed to initialize sensor (%d)\n",
63 ret);
64 return ret;
65 }
66 }
67
68 thermal_zone = devm_thermal_of_zone_register(dev: &pdev->dev,
69 id: 0,
70 data: sensor,
71 ops: &thermal_mmio_ops);
72 if (IS_ERR(ptr: thermal_zone)) {
73 dev_err(&pdev->dev,
74 "failed to register sensor (%ld)\n",
75 PTR_ERR(thermal_zone));
76 return PTR_ERR(ptr: thermal_zone);
77 }
78
79 thermal_mmio_get_temperature(tz: thermal_zone, temp: &temperature);
80 dev_info(&pdev->dev,
81 "thermal mmio sensor %s registered, current temperature: %d\n",
82 pdev->name, temperature);
83
84 return 0;
85}
86
87static int al_thermal_init(struct platform_device *pdev,
88 struct thermal_mmio *sensor)
89{
90 sensor->read_mmio = thermal_mmio_readb;
91 sensor->mask = 0xff;
92 sensor->factor = 1000;
93
94 return 0;
95}
96
97static const struct of_device_id thermal_mmio_id_table[] = {
98 { .compatible = "amazon,al-thermal", .data = al_thermal_init},
99 {}
100};
101MODULE_DEVICE_TABLE(of, thermal_mmio_id_table);
102
103static struct platform_driver thermal_mmio_driver = {
104 .probe = thermal_mmio_probe,
105 .driver = {
106 .name = "thermal-mmio",
107 .of_match_table = thermal_mmio_id_table,
108 },
109};
110
111module_platform_driver(thermal_mmio_driver);
112
113MODULE_AUTHOR("Talel Shenhar <talel@amazon.com>");
114MODULE_DESCRIPTION("Thermal MMIO Driver");
115MODULE_LICENSE("GPL v2");
116

source code of linux/drivers/thermal/thermal_mmio.c